1. Field of the Invention
The present invention relates generally to the structure and use of surgical instruments, and more particularly, to a device and method for applying and knotting suture in locations having limited access.
Least invasive surgical (LIS) techniques, such as laparoscopic, endoscopic, and arthroscopic surgery, are generally performed through small incisions using specialized instruments to perform desired surgical procedures. Usually, the instruments are introduced through a tube, such as a cannula, while the physician observes manipulation of the instruments through specialized imaging equipment, such as laparoscopes, endoscopes, and arthroscopes. Such LIS techniques offer significant advantages over conventional "open" surgical procedures. In particular, the LIS techniques are usually less traumatic, require a shorter recovery time, and are less costly than the corresponding conventional surgical techniques.
While such LIS procedures have been very successful, improvements in the instruments and techniques which are employed will enhance the efficiency of those procedures which are presently performed and potentially extend the application of LIS techniques to new surgical procedures. In particular, it would be desirable to improve the design of LIS instruments so that they are more readily manipulable, better able to perform specific tasks, less likely to expose the patient to inadvertent injury, and the like.
Of particular interest to the present invention are LIS instruments for applying and tying suture at remote locations. Heretofore, the most common approaches for tying suture have been to manually tie a knot in the free ends of the suture outside of the cannula and to push the knot forward through the cannula using a rod or to tie the knot in situ using instruments. While workable, such techniques are time consuming, limit the type of knot which can be formed, and usually require at least two tying steps to form a tight knot. Thus, it would be desirable to provide improved methods and instruments for applying and tying suture at remote locations.
One improvement which has been proposed is the use of preformed knotted loops in suture. Such knotted loops allow the suture to be tied by passing a free end of the suture through the loop and tightening the loop on the suture after the wound has been closed. Such a technique and an instrument for performing the technique are described in U.S. Pat. No. 4,760,848, described further hereinbelow. The instrument described in the '848 patent, however, is deficient in certain respects. In particular, the instrument must release the knotted loop prior to passing the free end of the suture therethrough. Thus, the loop can be temporarily lost by the physician, making tying of the knot problematic. The instrument described further lacks any capability for tightening the knotted loop to facilitate tying of the free end of the suture. It would be desirable if the instrument carrying the loop were able to hold the knotted loop during the entire procedure and to tighten the knotted loop without the need to employ a separate instrument.
2. Description of the Relevant Art
U.S. Pat. No. 4,760,848, describes a surgical instrument having a pair of jaws at a distal end of a tube. The jaws may be used for carrying a surgical needle which is attached to a length of suture. The suture may have a preformed loop with a slip knot that allows the suture to be tied by passing the needle back through the loop. U.S. Pat. Nos. 4,923,461 and 4,602,635, describe surgical knotting devices where a knot is tied externally and the knot pushed forward to the tissue being sutured. Other remote surgical knotting devices are described in U.S. Pat. Nos. 4,641,652 and 3,871,379.